Did you know?

Click any word in a definition or example to find the entry for that word


 - definition

What are red words?

90% of the time, speakers of English use just 7,500 words in speech and writing. These words appear in red, and are graded with stars. One-star words are frequent, two-star words are more frequent, and three-star words are the most frequent.



The thesaurus of synonyms and related words is fully integrated into the dictionary entries. Click on the T button in an entry to review the synonyms and related words for that meaning.

noun [countable/uncountable] interaction pronunciation in American English /ˌɪntərˈækʃən/ 
Word Forms
  1. 1
    the activity of being with and talking to other people, and the way that people react to each other
    interaction with:

    I enjoy the constant interaction with people from other departments.

    interaction between:

    the interaction between mother and baby

    social interaction:

    Jobs that involve a degree of social interaction are usually more satisfying.

  2. 2
    the process by which different things affect each other or change each other
    interaction of:

    the interaction of these two medications

    interaction between:

    the interaction between an organism and its environment

    interaction with:

    The mechanism seems to involve interactions with other proteins.


a paid holiday given to a new employee before they start their job

BuzzWord Article

Open Dictionary

selfie stick

an expandable stick which you attach to a mobile phone or camera to help you take a selfie …

add a word


A must for anyone with an interest in the changing face of language. The Macmillan Dictionary blog explores English as it is spoken around the world today.

global English and language change from our blog